#include<stdio.h>
#include<math.h>
int main()
{
    float a, b, c, x1, x2;
    printf("enter the value of abc:\n");
    scanf("%f %f %f", &a, &b, &c);//
    if (b*b - 4 * a*c < 0)//判断方程是否有实根
    {
        printf("unsolvable");
    }
    else//如果有解就打印出方程的根
    {
        x1 = (-b + sqrt(b * b - 4 * a*c)) / (2 * a);
        x2 = (-b - sqrt(b * b - 4 * a*c)) / (2 * a);
        printf("输出为：x1=%0.2f,x2=%0.2f", x1, x2);
    }
    return 0;
}